Document Type

Thesis - Open Access

Award Date

2022

Degree Name

Master of Science (MS)

Department / School

Agronomy, Horticulture, and Plant Science

First Advisor

Dwayne Beck

Keywords

Crop rotations, No-till, Soil quality

Abstract

No-till is increasingly promoted as a vital agricultural practice to address the challenge of improving soil quality while maintaining the ability to produce food, feed, fuel, and fiber. However, questions remain regarding 1) how different crop rotations impact soil quality under no-till management specifically and 2) whether significant improvements in soil quality can be made without negatively impacted crop yields. In this study, we demonstrate that even under the same long-term no-till management, differences in grain yields and soil biological, chemical, and physical properties exist between crop rotations at Dakota Lakes Research Farm in central South Dakota. We propose that these differences in soil quality and grain yields are due to the proportions of high residue producing crops and the diversity of crops included in the crop rotations. In this study, irrigated rotations included corn-soy (low diversity, 50% high residue crops), corn-corn-soy-wheat/cover crop-soy (high diversity, 60% high residue crops), corn-cornsoy- wheat/cover crop (medium diversity, 75% high residue crops), and continuous corn (low diversity, 100% high residue crops). Dryland rotations included wheat-broadleafcorn- broadleaf (high diversity, 50% high residue crops), wheat-corn-broadleaf (medium diversity, 67% high residue crops), and wheat-wheat-sorghum-corn-broadleaf (high diversity, 80% high residue crops). Rotations which had both mid to high crop diversity and mid to high proportions of high residue crops exhibited enhanced soil quality properties (such as larger mean soil aggregate sizes and higher soil organic carbon contents) and maintained or increased grain yields over time (1991-2021) at Dakota Lakes Research Farm. These results suggest that crop rotation management must be promoted in addition to no-till management to simultaneously improve soil quality, crop yields, and agricultural sustainability.

Library of Congress Subject Headings

No-tillage -- South Dakota.
Crop rotation -- South Dakota.
Soils -- Quality -- South Dakota.
Grain -- Yields -- South Dakota.

Number of Pages

156

Publisher

South Dakota State University

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Rights Statement

In Copyright